I have prepared Carbon frameworks at 700 and 800(degree C) temperatures. The Surface area obtained for 700 (degree C) is higher than 800 (degree C).
In general the BET surface area decreases with increasing temperature due to sintering or collapse of smaller diameter pores.
In general the BET surface area decreases with increasing temperature due to sintering or collapse of smaller diameter pores.
Sintering in general it activates the diffusion and transfert of mater on the surface of the material. If the temperature of sintering is somwhere abetween 0,5 to 0,9 of the melting temperature point the pores start to close due to grouth of the particles
Zahira Bano What atmosphere was used to generate your carbons, and from what pre-cursor? How about holding time at max T? One would normally expect the higher temperature and longer times to generate higher surface area, e.g. Article Unprecedented CO 2 uptake over highly porous N-doped activat...
I don't expect carbons to sinter in the normal way we think of ceramics (and metals) at the temperatures you indicate.
You didn't indicate how much higher... by a lot or just a little (within experimental error?).
Do I assume correctly that the surface areas were determined by nitrogen adsorption at 77K? It would be interesting to analyze your samples using CO2 at 273K as CO2 can more easily and more quickly enter into pores critically sized or even smaller than the nitrogen molecule. Though not normally the case for carbons, it might nevertheless be enlightening to look at your samples using CO2.
Martin A Thomas The temperature difference is 100 degree C and time for both the samples was 1hour. Yes i measured surface area by nitrogen adsorption at 77K. Thankyou for your suggestions i will analyze using CO2 at 273k to see the difference.
The Surface area at 700 degree is 567.7 m2/g and at 800 is
498.15 m2/g.
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